The shaft of an endoscope comprises several tubes positioned inside one another. Lightwave conductors, for instance, for transmitting light for illuminating a cavity to be examined, are positioned in the hollow spaces between these tubes. During a medical procedure, the shaft of a rigid endoscope can be subjected by the medical staff to a considerable mechanical impact, in particular a bending impact. Considerable medical stresses can also arise during autoclaving because of differing thermal expansion coefficients of different components or because of temperature gradients.
Mechanical bending of a tube because of corresponding mechanical impact or also because of thermal stresses during autoclaving deforms the hollow spaces between the tubes. Lightwave conductors, electric conductors, or other functional elements positioned in the hollow spaces can thereby be pushed, stretched, compressed, squeezed, ground, or otherwise damaged. In addition, bending of the tubes and the resulting sliding of lightwave conductors can result in a one-sided, irregular illumination of the space before the distal end of the endoscope.
To avoid any deforming of hollow spaces between tubes that are positioned inside one another in a shaft of an endoscope, wire pieces or blade segments that conventionally run essentially in the longitudinal direction are welded, soldered, or cemented to the inner tube in each case. Lightwave conductors and other devices can be positioned between the wire pieces or blade segments in the interior space between the tubes. The wire pieces or blade segments service to mechanically support each of the inner tubes in each case with respect to each of the outer tubes. As a result, deformation of the hollow space is reduced and the rigidity of the shaft is increased by the distribution of mechanical stresses onto both tubes.
Positioning and joining the wire pieces or blade segments on the respective inner tube, however, is time-consuming as well as laborious and thus cost-intensive. In addition, the blade segments joined to the inner tube must then be adjusted to the inner contour of the outer tube, for instance by overwinding. In the process, the wire pieces or blade segments can again be torn off.